Means for preventing spots in paper



(N\0 Model.)

B. W. ALLAN. MEANS FOR PREVENTING SPOTS IN PAPER.

No. 480,446. Patented Aug. 9, 1892.

W3 r O 1a w by 1th I Jll Mn HIM i A \s WK M r I W m k u H lLflJ H hvwewboz am mm W 4 UNITED STATES PATENT OFFICE.

ROBERT W. ALLAN, or FAIR'FIELD, ASSIGNOR on ONE-HALF TO ROSWELL M.FAIRFIELD, HOLYOKE, MASSACHUSETTS.

MEANS FOR PREVENTING SPOTS lN PAPER.

SPECIFICATION forming part of Letters Patent No. 480,446, dated August9, 1892. pp i ati n filed November 12. 1889. Renewed December 31, 1891.Serial No. 416,730. (No model.)

To all whom may concern.-

1 3e it known that I, ROBERT W. ALLAN, of Falrfield, in the county ofHampden and State of Massachusetts, have invented a new and usefulImprovement in Means for Preventing Spots in Paper, of which thefollowing is a specification, reference being had to the accompanyingdrawings forming part thereof.

My invention relates to apparatus to be used in the manufacture ofpaper, and partlcularly of fine writing and other papers; and it has forits object to provide means to housed in connection with the usualFourdrlnier or other machine for making paper for preventing the passageof What are known as blue spots and collections of fiber or stringymatter to the machine, where they would, if not intercepted, cause ablemish in the paper.

In the manufacture of paper the stuff is pumped from the stuff-chest tothe stuff-box and from the latter passes to and through a screen, theoflice of which is to remove there from all knots and undigested lumpsof fibrous matter, and from said screen the stuff passes to the machine.The screening-surface of said screen is given a rapid vibration,particularly in the well-known and generally-- used Gould screen, andsuch vibration frequently causes the formation of drops of the stuff,which fall upon the surface of the stream of stuff issuing from thescreen, and there being no intervening agitator to disintegrate saiddrops they are carried to and upon the machine, and the bluing-matterintroduced into the stuff to secure perfect whiteness of the papercontained in said drops causes a blue spot in the paper. Such blue spotsrender the paper containing them unsalable, and the waste caused therebyis a source of much loss to the manufacturer. Again, it often happensthat lumps or collections of stringy or fibrous matter remain in thestuff after the latter has passed through the screen, and these alsocause a blemish in the paper, which necessitates condemning the latter.I have found that all such causes of blemish in the paper can be removedby introducing into the path of the stuff, between the screen and themachine, an agitator and by compelling the stuff to pass through saidagitator; and my invention therefore consists in the combination withsaid paper-machine and said screen, of an agitator located between them,as hereinafter fully described, and particularly pointed out in theclaims.

Referring to the drawings, in which like letters designate like parts inthe several figures, Figure l is an end elevation of apapermachine andof a Gould screen, illustrating the position relative thereto of theagitator devised by me and showing the latter in vertical section. Fig.2 is a longitudinal vertical section of the agitator.

The letters A andB designate so much of a paper-machine and a Gouldscreen, respectfully, as is necessary to be shown in order to illustratethe application of my invention thereto.

The letter a designates the usual trough or conduit leading to themachine, and b the pipe by Which the stuff is conducted from the screeninto said trough.

As hereinbefore stated, the vibration of the screeningsurface of theGould and other screens frequently causes the formation of globules ordrops of the stuff, which pass to the machine unbroken and cause a bluespot in the paper, and in carrying out my invention for preventing theformation of said blue spots, as well as for preventing the passage tothe machine of stringy and fibrous collections of the stuff which maypass through the screen, I locate at some point between the screen andthe machine an agitator constructed to thoroughly agitate the stuff andcause the stuff to pass through said agitator in its passage from thescreen to the machine.

I prefer to make the agitator of the form shown at C in the drawings,consisting of a rectangular box supported upon suitable legs orstandards and having centrally located near the bottom thereof a shaft0, provided with the short paddles c, projecting radially therefrom,said shaft having its bearings in the ends of the box and carrying atone end band-pulley 0 whereby motion can be transmitted thereto from asuitably-disposed counter-shaft. A central partition 0 is secured to theends of the box, said partition extending downwardly to within a shortdistance of said shaft. In practice I prefer to leave only substantiallyone-half inch of space between the outer ends of the paddles on saidshaft and the bottom of the box and between the ends of said paddles andthe bottom of said partition 0 As before stated, the agitator thusconstructed can be located at any point between the screen and thepaper-machine; but I prefer to locate it at some point in the trough orconduit a, as shown in Fig. 1. When thus located, the top of the boxmakes a tight joint with the bottom of the trough, and a portion or allof said bottom between the sides of the box is removed to afford opencommunication between the trough and the box. The central partition ofthe box is extended upwardly to a point where its upper end is flushwith the sides of trough a, as shown,and thus compels the stuff to passdownwardly upon one side thereof beneath its lower end and upwardly uponthe opposite side thereof in its passage from the screen to the machine.As the stud passes beneath said partition the rapidly-revolving shaft 0thoroughly agitates every portion thereof, diffusing the globules ordrops and disintegrating the lumps or collections of stringy and fibrousmatter, which would otherwise cause blue spots and other blemishes inthe paper, in such manner that the paper issues from the machine freefrom blemish. A very material saving to the manufacturer is thus securedby the use of the simple and inexpensive apparatus herein described.

I do not wish to limit myself to the particular form or relativedimensions of the agitator nor to the exact location thereof hereinshown and described, it being obvious that modifications therein can bemade within the spirit of my invention.

Having thus fully described my invention, what I claim, and desire tosecure by Letters Patent, is

1. The combination, with a paper-machine and ascreen for screening thestuff prior to its deliveryto said machine, of an agitator locatedbetween said screen and said machine and means, substantially asdescribed, for compelling the stuff to pass through said agitator in itspassage from the former to the latter, substantially as and for thepurpose set forth.

2. The combination, with a stuft-screen and a paper-machine, of aconduit leading from the former to the latter and an agitator located insaid conduit, substantially as and for the purpose described.

3. The combination, with a stuff-screen and a paper-machine, of aconduit leading from the former to the latter and an agitator located insaid conduit, said agitator being composed of a box having a passage-wayleading therethrough, which passage-way is in open communication at eachend with said conduit, and having located within said passageway arevoluble shaft provided with radially-dis posed arms or paddles,substantially as and for the purpose described.

4:. The combination, with a stu tf-screen and a paper-machine, of aconduit leading from the former to the latter, a box located beneathsaid conduit and having itstop in open communication with the latter,said box having a centrally-disposed partition extending from apointabove the bottom thereof to and within said conduit, and a revolubleshaft located within said box between the bottom of the latter and thebottom of said partition, said shaft having radially-disposed arms orpaddles, arranged and operating substantially as described.

5. The combination, with a paper-machine and a stuff-screen, of aconduit, as a, leading to said machine, a pipe, as 1), leading from saidscreen into said conduit, box C, located beneath said conduit and havingopen communication at its upper end with the interior of the latter,said box having partition 0 centrally located therein and extendingupwardly from a point near the bottom thereof to the top of saidconduit, and shaft 0, provided with paddles c and carrying band-pulley 0located within said box between the lower end of said partition and thebottom of the box and having its hearings in the ends of said box,arranged and operating substantially as and for the purpose described.

' ROBERT W. ALLAN.

Witnesses:

W. H. CHAPMAN, J. E. CHAPMAN.

